Emoji table column misalignment regression (v1.0.43) — #2764 not fully fixed

## Description

#2764 was closed as fixed in v1.0.32, but emoji column misalignment persists in v1.0.43. Emoji characters in table cells cause column borders to shift and extra `|` pipe characters render inside cells.

## Steps to Reproduce

Prompt:
```
echo this table back to me | Test | Rate | Status | Fix |
|------|------|--------|-----|
| FooTest | 12/12 | ❌ Unresolved | #123 didn't fix |
| BarTest | 7/12 | 🔧 Merged | #456 May 8 |
| BazTest | 6/12 | 🔶 Partial | #789: 100%→25% |
| QuxTest | 4/12 | ❓ No fix | — |
| QuuxTest | 3/12 | ✅ Ready | PR #101 |
| CorgeTest | 2/12 | 🟡 Flaky | — |
```

## Expected

Columns align correctly. Emoji counted as correct display width.

## Actual

- Status column with emoji shifts subsequent column borders right
- Extra `|` pipe characters appear inside rendered cells
- Column widths inconsistent between rows with different emoji

## Environment

- Copilot CLI version: 1.0.43
- OS: macOS
- Terminal: IntelliJ built-in terminal
- Shell: zsh

## Ref

- #2764 — originally reported, closed as fixed in v1.0.32
- Fix claim: "Tables render with correct column widths, emoji support, and stable borders during terminal resize"